Threshold switching and current controlled negative differential resistance effects have been achieved by two terminal devices utilizing a wide variety of amorphous semiconductors, such as glasses from the As.sub.2 (Se,Te).sub.3 system. For these devices to be used extensively, that is, to gain wide acceptance by the technical community, the amorphous semiconductor material must be highly resistant to devitrification, that is, have a high glass transition temperature, and be easily manufactured into a thin film. The As.sub.2 (Se,Te).sub. 3 system of glasses are not easily manufactured, requiring flash evaporation deposition, and have a glass transition temperature of only about 110.degree.-170.degree.C.